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How much has Ontario warmed?

Each stripe below is one year of average temperature in San Bernardino County, from 1895 on the left to 2025 on the right. Blue years were cooler than the 20th-century average of 65.1°F, and red years were warmer.

1895: -1.0°F1896: +0.9°F1897: -1.1°F1898: 0.0°F1899: -0.6°F1900: -0.1°F1901: +0.3°F1902: -1.0°F1903: -1.4°F1904: 0.0°F1905: -0.7°F1906: -0.3°F1907: -1.1°F1908: -2.0°F1909: -1.9°F1910: +0.7°F1911: -2.0°F1912: -2.3°F1913: -1.8°F1914: -0.3°F1915: -1.4°F1916: -2.2°F1917: -1.2°F1918: -1.5°F1919: -1.7°F1920: -1.8°F1921: -0.2°F1922: -1.2°F1923: -1.3°F1924: -0.4°F1925: -0.6°F1926: +0.5°F1927: -0.2°F1928: +0.1°F1929: -0.2°F1930: -0.8°F1931: +0.3°F1932: -0.7°F1933: -0.5°F1934: +2.5°F1935: -0.6°F1936: +1.3°F1937: +0.2°F1938: -0.2°F1939: +0.5°F1940: +1.4°F1941: -1.5°F1942: -0.1°F1943: +0.7°F1944: -2.0°F1945: -0.7°F1946: -0.1°F1947: +0.5°F1948: -1.4°F1949: -1.4°F1950: +1.3°F1951: -0.5°F1952: -0.8°F1953: -0.2°F1954: +1.0°F1955: -1.1°F1956: -0.1°F1957: -0.2°F1958: +1.3°F1959: +1.7°F1960: +0.9°F1961: +0.4°F1962: +0.8°F1963: +0.1°F1964: -0.8°F1965: -0.7°F1966: +0.8°F1967: +0.3°F1968: +0.3°F1969: +0.7°F1970: +0.4°F1971: -0.8°F1972: +0.4°F1973: -0.3°F1974: +0.7°F1975: -0.8°F1976: +0.1°F1977: +1.0°F1978: +0.3°F1979: +0.1°F1980: +1.3°F1981: +2.6°F1982: -0.7°F1983: +0.1°F1984: +1.1°F1985: +0.3°F1986: +1.6°F1987: +0.5°F1988: +1.5°F1989: +1.8°F1990: +0.9°F1991: +0.5°F1992: +1.3°F1993: +0.5°F1994: +1.2°F1995: +1.9°F1996: +2.9°F1997: +2.0°F1998: -0.9°F1999: +1.2°F2000: +2.2°F2001: +2.1°F2002: +1.9°F2003: +2.5°F2004: +1.3°F2005: +1.3°F2006: +1.9°F2007: +2.4°F2008: +1.9°F2009: +1.7°F2010: +0.7°F2011: +0.5°F2012: +3.0°F2013: +1.9°F2014: +4.0°F2015: +3.1°F2016: +3.1°F2017: +3.6°F2018: +3.4°F2019: +0.5°F2020: +3.1°F2021: +3.4°F2022: +3.0°F2023: +0.7°F2024: +3.4°F2025: +3.4°F
1895Ontario, yearly average temperature2025

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Last 10 years
+2.7°F2016-2025 vs the 1901-2000 average
Warmest year
2025then 2024, 2021, 2017
Coldest year
1912in the 1895-2025 record
20th-century average
65.1°Fall months, San Bernardino County

Decade by decade

-0.4°1890s
-0.8°1900s
-1.4°1910s
-0.5°1920s
+0.2°1930s
-0.5°1940s
+0.2°1950s
+0.3°1960s
+0.1°1970s
+1.0°1980s
+1.2°1990s
+1.9°2000s
+2.4°2010s
+2.8°2020-25

Average difference from the 1901-2000 average, by decade. The 2020s cover 2020 to 2025.

Nearby cities

See which cities have warmed the most in our warming ranking, or today's normal weather month by month in Ontario.

Frequently asked questions

How much warmer is Ontario than it used to be?

In San Bernardino County, the ten years from 2016 to 2025 averaged 2.7°F warmer than the 20th-century average of 65.1°F, according to NOAA's county temperature records.

What was the warmest year on record in Ontario?

The warmest years in NOAA's county record are 2025, 2024, 2021, 2017 and 2014. The coldest was 1912.

What are climate stripes?

Each stripe is one year. Its color shows how that year's average temperature compares with the long-term average: blue for cooler, red for warmer, darker for bigger differences. The design comes from climate scientist Ed Hawkins.

Source: NOAA National Centers for Environmental Information, nClimDiv county average temperature (version 1.0.0, October 2026 release). Values are county averages built from adjusted weather station records on a 5 km grid, so they describe San Bernardino County as a whole rather than downtown Ontario, and they correct for changes in stations and instruments over time. Incomplete years are left out. Stripes design by Ed Hawkins (#ShowYourStripes).